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Nytro Bent Front End this one has hit nothing WITH PICTURES

NOS-PRO said:
Skis look to be back where they were, and could see the shock moving in the upper a-arm, but looked like the bottom a-arm was moving forward.
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I have all new a-arm bushings on order for mine because I think they are too sloppy. I talked to dealer on the phone and he is insistent the play is from the lower balljoint(even though he hasn't seen mine, he's seen a few others). someone mentioned greaseable balljoints, anyone have a supplier or part #?

oh yeah, welcome to the club!! there are 2 types of nytro owners. those that have tweaked their front end, and those that will.
 

Crewchief47 said:
Posts like this kill me. Do you guys honestly think Yamaha uses green riders to test the new iron??? Whatever! Perhaps they need to use greener/less experienced riders that aren't as smooth or efficient in thier riding.
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Eh? What are you trying to say?

What I know for certain is the guys I ride with, with only 2 weeks worth of riding, can demonstrate pretty much all of the weak links in our 05 through 07 RX-1/Apex sleds. Most of us are between 40 and 55 years old and have been sledding for at least 25 years. If Yamaha has test riders who put on high miles and ride aggressively then they must be turning a blind eye to fatigue cracks in pivot arms, fatigue cracks in slide rails, leaking chaincases, blown idler wheels, broken RA adjusters, etc. Every one of us has had each of the issues mentioned above and in every case in less than 2 weeks worth of riding (I can also tell you the 07 Apex RTX doesn't have the weak links - at least once the chaincase cover is updated and idler wheels are replaced). A couple more weeks worth of riding and we all start to have the same exhaust donut leaks and exhaust system components cracking.

I don't know if we'd tweak the front end on a Nytro, but based on the experience with the Apex line I wouldn't be surprised at all if we did. Every single fatigue failure and leak ever mentioned here on TY4stroke.com has happened to our sleds.

What type of rider does Yamaha use for their test riders? Do they push the rough trail sleds hard on rough trails, or take it easy doing a few 100 miles on smooth trails? Does Yamaha know all of the weak links before they sell us a sled or do they find out the expensive way - once 1000's of sleds are sold and under warranty? I'm convinced they are (or have been) taken by surprise in the past.
 
My front end is now tweaked as well but it was due to me being stupid and going way to fast. Last Tuesday night I hit a series of wind drifts on the trail right by my home while going at least 80 MPH. I held on for the first seven drifts, which crossed the trail at a 45 degree angle towards me. The first few drifts popped the rear of my sled up in the air, endo style, and the bars whipped back and forth in my hands. The sled then started swapping and the 8th drift was steeper and bigger (like 2' high) and I instinctively knew the sled was kicked out too far to the right so I bailed. The machine ended up rolling, did a cart wheel and came to a stop facing backwards on the trail, right side up.

Long story short, my right ski tip was bent upwards, the right spindle was more vertical and the right shock spring was 5mm away form the back of the top a-arm compared to 10 mm for the left shock.

So far I have not found anything bent in the front clip. The RH lower a-arm has a tweak since it will slightly rock when set on a flat surface compared to the LH lower a-arm. I'm just going to tweak things back into shape and ride it.

I'm actually impressed by how well the sled took the wreck. My stock windshield broke off on the plastic screws and my bars don't even seem bent. The RH tie rod was bowed and the RH floorboard bent upwards in a V.

I know guys are reinforcing their a-arms and spindles but I've been hesitant to do so until we know why things are bending. After my wreck, I'm glad the parts were stock because I think had I reinforced the a-arms, the impact forces would have been transmitted somewhere more expensive. Those aluminum spars that the front clip bolts to are kind of cantilevered out there and the motor mounts are tie into them. I'm thinking there are some good reasons why the Yamaha engineers designed the front end the way they did.
 
I'm going to brace the sub frame and the spindles, but leave the a-arms alone. Hopefully with a large enough impact it will only bend an a-arm. I would hate to have the sled so beefed up that if you had a bad crash instead of taking out an a-arm you bent one of the cast bulkhead pieces $$$$

I don't have my front end completely apart yet, but it almost seems like only an a-arm is bent, I can't visually see any bends in the sub frame.
 
When you get around to it Nikolai, take a pic of the a arm that appears to be bent so we'll know what to look for. If it isn't the subframe we should be looking at, and since you have already begun to take yours apart, it would save us a whole lot of time by not having to take the subframe off from the sled. ;)!

I'm still confused as to how the upper a arms are now in question when in most cases, the spindle appears to be more straight up and down, and this side's ski ends up being pushed further back than the other side's ski, should be the other way around when you think about it. I guess pics and measurements are the only way to really know for sure...
 
Definately check the lower A arms. I thought I had bent the subframe as well because I could not see any visible cracks or creases in the A arm. I ended up buying a new A arm and sure enough it was the culprit. I just wish there was a way to make the ball joints on the A Arm(lower) last longer. I don't think the slop in the front end is helping anything.

Edit: Just saw the IronDog posts. Thanks to 08Nitro RTX for all the tips.
 
If it's the a-arms, it's deffinitely the lowers. The uppers wouldn't cause the bottom of the spindle to twist back.

I'll take some pics when I get the front end the rest of the way apart but it might be another day.
 
The dealer cannot find anything bent on my sled, they took all measurments that Yamaha canada requested, sub frame, A Arms .... Nothing. The nest step is swap A-arms and shocks with their demo, hopefully a A-arm. Date on a subframe is March. That being said I took my sled back today, 300+km of riding tommorow. 1 ski back 1/2 a inch doesn't bother me that much.
 
New to this particular forum, been sledding for 20 some years. Just bought a Nytro on Thursday, put 90 powder miles on it this past weekend and have never had so much riding a sled. Luckily my front end is still straight, hope it stays that way.... Put a skid plate on tonight and did notice quite a bit of play in the top A-Arm, thought that was quite strange for Yammie, thought I was working on an Arctic Cat or something.... How difficult is the sub frame to remove an replace, has anyone done it?? Hope Yammie finds a fix soon.. Wonder if they will have an actual full blown recall since it's really not a safety issue and probably would not leave you stranded unlike other manufacturer's issues. IMO the "fun factor" of this sled out weighs this issue, although still annoying...
Thanks!! ;)!
 
With my sled, the spindle was rotated backwards at the bottom causing it to be more straight up & down compared to the undamaged side. I could not see anything visibly bent in the front clip. The a-arms easily slid in and out of the mounts when I removed and reinstalled them.

I ended up using a big pry bar and "untwisted" the a-arms. I was amazed by how much they flexed. My a-arms did not exhibit any cracks in the paint or obvious bends. I think because the spindles are set up to "float" between the arms, they are far more susceptable to caster changes than the DB-1 front end where the ends of the a-arms are held in place by horizontal bolts.
 
AKrider said:
I ended up using a big pry bar and "untwisted" the a-arms. I was amazed by how much they flexed. My a-arms did not exhibit any cracks in the paint or obvious bends. I think because the spindles are set up to "float" between the arms, they are far more susceptable to caster changes than the DB-1 front end where the ends of the a-arms are held in place by horizontal bolts.
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That's a pretty good point(about the DB spindles) and the bolts mounting it to the a-arms.

The other thing I wanted to point out was that the lower arm could be straight while the upper is twisted forward. Imagine the lower hiem/ball joint is the pivot. Apply a force to the bottom(ski) and the top moves the opposite direction. Now imagine the lower joint is moved closer to the ski, resulting in a reduction of the mechanical advantage the ski has over the upper(lever between the ski pivot and lower joint is shorter).

Now someone look at the race spindles and tell me if it looks like the lower joint is closer to the ski pivot.....
 
I can answer a couple questions:
*Takes about 45 min to remove front clip.
*They appear to be on back order (I don't know this myself just what I understand through talking with others)
*There IS a 'fix' in the works for our lower a-arm bearings. (I have NO idea how this will be handled through dealer and or Yamaha or we are own our own BUT I would guess the 09s will NOT have these same pieces in them)
*IMHO depending on the hit/ or strike it's the upper a-arm that is the weakest point up front. (with the spindle being right there in a very close second then the front frame) The upper a-arms are bending where they mount to the through tube that the mounting bolt goes through.
* Boxing in or cross tieing the front frame helps it from tweaking.


As was mentioned the real problem IMHO is once we start beefing something up, where do we stop as we continue to move/chase the weak point! Hit something with enough force SOMETHING has to give!
What I don't understand is the guys saying they haven't hit anything!!! But still encuring damage?? This one baffles me mainly because I have hit bumps and jumps and rough trail sections HARD and was still straight (before making changes)

I am disapointed in the plastic bushings we're running in the a-arms and these lower bearings! There needs to be a fix for this for all of us because as that lower a-arm bearing starts to fail it has a 'slidhammer effect' off every bump!
 
Thease frount ends are very weak . put a block under the center of the ski and push the ski tip down and see how easy it will bend . on my RX1 the ski will bend before the a-arms flex .
Tom-RX1
 
Jeff's post reminded me of my crappy stock bushings. My sled has between 750-800 miles and the plastic bushings allowed for a ton of slop. What I found most interesting is when I replaced all my bushings with much higher quality oil-lite bushings, the misalignment measurements actually decreased. My a-arms are now completely rock solid, no movement, no slop.

During this exercise I also discovered my LH lower ball joint was in the process of puking out its bearing material. The stock ball joints are junk and better quality replacements are in the works.

One other thing I've been thinking about was when my sled cart wheeled, the impact went into the RH side and my Ultra Flex III ski tip was so folded back that it stayed more bent back than the undamaged LH ski. I'm wondering if the flex in the ski helped absorb enough of the impact that it saved my front clip? I've not compared it to my stock Yamaha skis, but they may not flex as much?

I agree Crewchief, I'm going compare the Nytro spindle to what Doo and Pol are doing.
 
Also incase you guys didn't know the MTX and short track FX Nytros have different upper A-arms...

But in stock form the front suspension components have WAY to much 'flex' in them!
I have faith Yamaha will figure this out and as a COMPLETY new model sled I still think they did pretty darn good with the FX Nytro.
No not perfect and yes it should be improved upon for 09!
 
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